With the development of data storage technology, various data storage devices provide users with a higher data storage capacity, and data access speed has also been enhanced to a large extent. The development of network technology opens up new directions for data storage, and data storage devices are no longer limited to be locally deployed on data access devices but may be located at any physical locations accessible via a network.
Until recently there has been developed network attached storage, which is a burgeoning data storage technology. By this technology, a storage device attached to a network can provide centralized data access services to users connected to the network. Specifically, a NAS system may be a high-performance file sharing and storage device, and users using NAS can share files via an IP network.
Network attached storage is widely adopted in large enterprises, especially transnational corporations. At the beginning of establishing a NAS system, typically an enterprise only deploys a couple of servers for data storage; with the expansion of the enterprise scale and the increase of branches, the enterprise starts to gradually expand the original server capacity and deploys more servers at a plurality of physical locations (e.g., different cities in different countries/regions).
In order to facilitate the management of servers distributed at different physical locations, a technical solution termed network attached storage federation/aggregation has been developed nowadays, which solution allows access to data having different servers via a global namespace. However, there exists a problem in the federation/aggregation: since the federation/aggregation is distributed at a plurality of physical locations, when these physical locations are too far apart or network communication bandwidths between them are not satisfactory, memories' response time to data access becomes longer, and data access efficiency is reduced.